What happens to the diaphragm during the inspiratory phase of breathing?

During the inspiratory phase of breathing, the diaphragm contracts and moves downward. This contraction increases the volume of the thoracic cavity, allowing air to flow into the lungs due to the decreased pressure created within the thoracic cavity. When the diaphragm contracts, it pulls the central tendon down, which in turn pulls the entire diaphragm dome downward, facilitating the inhalation process.

The option stating that the diaphragm relaxes and lowers does not accurately describe what occurs during inspiration; rather, that would pertain to the process of exhalation where the diaphragm relaxes and moves upwards as air is expelled from the lungs. Understanding the mechanics of the diaphragm's movement helps clarify how breathing is facilitated during different phases.